Pneumatic counterweight



Oct. 9, 1951 M. J. MEYLiCH 2,571,049

PNEUMATIC COUNTERWEIGHT Filed Nov. 9, 1946 I 2 Sheets-Sheet 1 Fill &

l' l m ni f INVENTOR M.J. ME YL /C H ATTORNEY Oct. 9, 1951 M. J. MEYLlCHPNEUMATIC COUNTERWEIGHT 2 Sheecs-Sheet 2 Filed Nov. 9. 1946 K INVENTORMJ.MEYL ICH ATTORNEY Patented Oct. 9, 1951 PNEUMATIC 'COUN'IERWEIGHT'Milton"J.IMeylich;:.West Orange, N. J assignor toWestern-Electric;Company;-,Incorporated,: N

York N. Y.',ga: ,corporation oLNWaYOrka Application November 9, 1946;Si'iaINmWOBJSB I I This invention relateste pneumatic :counterweights,and moreparticularly to variableapneue-i matic mechanisms for-counter-weighingz- .mai-- chine parts= movableif into "and" out ofoperatin'g positions;-

Standard hand operated milling machines em ploy operating units for themi11ing 'cutters-which include spindles -for the cutters= andv speedvreducingg drivingsmechanismse-' In such': millingma chinesr: the?conventional: counterweightszihave beenaemployedi to: counterweigh' theunitiandu its spindle only; The milling *cuttersito'zbe mounts:edionrthe' spindles of? such units'zmawweighi from': twentyefive toone-hundred? fifty pounds's and whenzthisiextra'zweight is addeditothewperatin'g; unit: ofthe milling'rmachine, extra: effort isrrequiredrby. the: operator: totmoveathee unitriaway'r from the work;

Anobject of the invention is to provide a pnene matic' counterweight:which: is: simple; in: strucr-fture:.andzhighlyiefiicientirimperatifmtto:maiintain;a=constantiiforceitmcounterweighr'a mnvahletr'ob-' ject;the-constant:forceebeingvariable with varia-n tions. in :thejweightofithe uniti;

Withzthis andz-otherrobjects, in'gviewwthe 1m vention comprises a:pneumatic counterweight foraaz movable-r object'i variable inweightritorber counterweighed comprising-tan air-z cylinderohavingaa:.:piston" operative lyqconnected to ",thHImOV-F able object, a:supplyrline :foraair: under: 'a-= given? high pressure? connected-etc afeed: line *ieading torthe air cylinder; and r a control unit disp'osed:in the feed line --,variable with: "variations in' the* weight: of themovable object 1-to maintaini'ther air in vthe-rfeed 'line to the-saircylinder at a se; lected: constant pressure to counterweigh-r the:movable object. v

Inithe"present embodiment of the invention, the movable object to becounterweighed is the tool driving unitlof a milliiiglmachin'e, theweight of. which is increased. depending uponthe :Weight of the tool orcutter mounted upon therdriving spindle; A gage is disposed in the feedline between the*"contro1 unit .and the; :air? cylinder, actuable. bythe air under pressure in thefeed line .andcalibrated in terms ofthercounterweighwinglithrust; As an example;.iftheweightl ofithe cutteraddedito the driving, unit'of the (machine is: fifty pounds, the controlvalve or unit- Zine the feedline is adjustedto' maintain a suflicientpressure in theifeedili'ne toithemir cylinder, this pressurerbeingdetermined. during the adjustment ofmthey; control unit by'ob'servingthe gage, to maintain at; fifty-pound thrust against thetunit.

Other"objects'andadvantages will be apparent from? th2-f0110Winglidetailed descriptloiriswh'entconsidered in conjunction awitlirthe*acoonipany-w ingtdrawings; whereiniz:

1: is: a" side-'1 elevational "view-:- of a'imillirrg machine-embodying%the-'-:invention'; and V Y Fig:.:2 is'aifront 'elevationaliView ofthe:strirltf-fthrewshownin lii'g; 1.v v

Referringinow to the drawings; 1 the" machi-ner employed: toil'lustratetheinvention?- incl'ud'esi 3 workrsupportnl 6adjustablerverticallyrrelative: to the? work: 'DOSitiOIl'i dependingupon the: thickness of the material "1| Iythe depthe of :th'e-cut:orfcut's tow-be. made therein-1 by' a selected cutteri'sor itool I 2 and:the-diameterrof': thercutterr In; machines; of thisvtype;mechanism:-is'eusually: employe'ditos move aaw. carriage :I 4 upon:which the-works! Ii is?- mountedvin a given'r-path' relative: to the--cutterf l 21 5 Thecutter? I 2 *is'v mounteds. upon 1a.:v driving:spindle" l 5 'WhiCh *isra part: off-at driving i: unit" 011-;mechanism-"'2 l fi'fincluding gears a to reduce the"; speedfromtthe'tspeed ofizitheinitial;drivingsmeans orimotorv Knot shown) to?the desired -speedf' of rotation for: the spindle; andtcutterzflThezuniti I6 is supported for verticalEmovementonxa:guide:-

thermoregathe? conventional counterweighing means z(not"shown) maybe"connected; to theu'nit l6i=130 :assist :ihi-zits movement-vertically"from: its operating position: This" counterweighing mech anis'm'-which' may be a part of the machine does not T compensate for "thevariable weights added t'o the unit 5 l6 by the' mounting of the cutters|2 thereon. These cutters,-which-m ayi weig1r= from twenty-five toone-hundred" fifty, pounds? increase the effortflrequired by v theoperator'to raise the unit l6 andflt'scutter" away; from the *work; lThe 'effi'ciency of" anoperator. d'ependsgreatly-t upon the energy{required to operate the, machine; By "'counterbalancing the unit "[6."witltitst cutter regardless of the addi) tionalweight the cutter addsto the. unit,',thefelement of. fatigue'is 'reduced to a minimum.

The pneumatic 1 counterweight L in .the ,t present; embodimentinclude's'an air cy1inderv25 pivotallii;

A supply line 3|, for air under a given high pressure greater than thatrequired at any time for the mechanism, leads to a control unit 32.

The control unit 32 is a commercially known brake valve having an inlet33 connected to the supply line, an outlet 34 connected to a feed line35 and an exhaust valve portion 36 operable to open an inner portion ofthe valve communicating with the feed line 35 to the atmosphere when thepressure in the feed line exceeds a selected pressure for which the unitor valve 32 has been set. The control unit 32 includes a plunger 38operable against the force of an internal spring to control an innermechanism to admit air to the feed line 35 from the supply line 3| undera reduced selected constant pressure. An adjustable screw 39 positionedin a threaded portion of a bracket 40,

mounted on the housing or frame of the machine and serving as a supportfor the valve or unit 32, is movable to adjust the position of theplunger 33 to set the control unit or valve 32 at anyselected'-'position whereby it will maintain a selected constantpressure of the air in the fluid line 35. The control unit 32 may be ofa well known type commonly used as a brake valve and in which theplunger 38 is actuated by a lever connected to, and operated by a brakepedal to apply selected constant pressure to braking units. In thepresent embodiment, the function of the valve 32 is to maintain aselected constant air pressure in the feed line 35 which leads to thebottom of the air cylinder 25 at the connection 42.

A gage 43 is connected in the feed line 35 between the control unit 32and the air cylinder 25 and includes a pointer 44 operated relative to adial 45 by the pressure of the air in the feed line. The dial 45 iscalibrated in terms of pounds corresponding to the pounds in weight ofany one of a plurality of cutters l2 mounted singly or in groups uponthe spindle 5. A cut-off valve 48 is mounted in the feed line 35 betweenthe gage 43 and the air cylinder 25 to shut off the air in the feed lineshould maintenance be required in connection with the air cylinder.

The structure indicated generally at 50 and shown in dotted lines inFig. 1 includes the conventional air jet receiving air under pressurefrom the supply line 3| to force the cuttings from the work around thecutter |'2.

To condition the pneumatic counterweight to counterbalance the unit l6and its cutter |2, the operator knowing the weight of the cutter adjuststhe screw 39 relative to the plunger 38 of the control valve 32 untilthe gage 43 registers the weight of the cutter |2 at which time thecontrol mecha-- nism is in readiness for the operation of the machine aslong as that particular cutter remains in use in the machine. All thatis required of the operator to move the chosen cutter-with the unit l6awa from the work is to move the handle 22 upwardly, substantially allof the force acting in the movement of the driving unit IS with thecutter results from the counterweighing mechanism present in the machinecoupled with pneumatic counterweight. As the unit |6 is raised, at thebeginning of its movement upwardly the piston in the air cylinder 25 ismoved upwardly increasing the space beneath the piston in the cylinder.At this time, the valve or control unit 32 will function to admit moreair from the supply line 3| into, the feed line 35 and eventually intothe air cylinder to maintain the selected pressure beneath the piston,urging it upwardly to counterweight the unit l6. When the unit I6 ismoved downwardly, a reverse action takes place in that the 4 air beneaththe piston in the air cylinder would be compressed and its pressureincreased were it not for the control unit 32. The control unit 32 willexhaust the excess air to the atmosphere through the exhaust portion 36,to maintain the air in the feed line 35, as well as in the air cylinder25, at the selected constant pressure.

The pneumatic counterweight has been shown and described in only oneembodiment, that for which it was originally designed. In thisembodiment, it serves as an auxiliary to a known type of counterweighingmeans which is ineffective to counterweigh any tool or other appreciablemass added to the previously balanced structure. However, if desired, itmay be used as the sole counterweighing mechanism of a machine and ineither event its use results in an accurate counterweighing of the wholestructure to be moved even though its weight is varied over aconsiderable range.

Although specific improvements of the invention have been shown anddescribed, it will be understood that they are but illustrative and thatvarious modifications may be made therein without departing from thescope and spirit of this invention as defined by the appended claim.

What is claimed is:

A pneumatic counterweight for a vertically slidable unit of a millingmachine operated by a mechanism under the control of a manually actuablelever, the unit having milling cutters selectively carried thereby andvarying in weight with variations in the number and sizes of the millingcutters carried by the unit, the pneumatic counterweight comprising anair cylinder mounted beneath the unit and having a piston movabletherein by air under pressure, a connecting element interposed betweenthe piston and the unit whereby a given force applied to the under sideof the piston by air under pressure will be translated to the unitthrough the connecting element, a supplyline for air under a given highpressure, a feed line leading from the supply line to the bottom of thecylinder beneath the piston, a control valve, having an actuableplunger, interposed between the supply line and the feed line, and a.member movable to actuate the plunger of the control valve and hold theplunger in any of a plurality of positions to first vary the pressure ofthe air in the feed line and beneath the piston with variations in theweights of the tools carried by the said operating unit, and thenmaintain the selected air pressure constant to counterweigh the unit andthe selected milling cutter carried thereby to minimize the effortrequired in manually actuating the lever to move the unit.

MILTON J. MEYLICH.

REFERENCES CITED The following references are of record inthe file ofthis patent:

UNITED STATES PATENTS Number

